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Microcosm Evaluation Of Natural And Biologically-Enhanced Abiotic Transformation Of Chlorinated Ethenes In Low Permeability Formations, Hao Wang

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Trichloroethene (TCE) is one of the most commonly found hazardous compounds at Superfund sites, especially in groundwater. Its volatility and toxicity pose a threat to drinking water safety and human health. In the past decades, research on the fate of TCE in the environment has shifted to contamination of low-permeability formations, for example fractured bedrock aquifers. TCE back-diffusion from low permeability zones and management of persistent TCE groundwater plumes caused by this long-term source zone pose major challenges for remediation.

Monitored natural attenuation (MNA) is a cost-effective remediation strategy that has gradually gained acceptance by regulators. Compared to extensive active …

Biodegradation And Bioremediation Of Hexachlorocyclohexane Isomers, Chlorinated Ethenes, Chlorinated Benzenes And Benzene, Vijaikrishnah Elango

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ABSTRACT
Groundwater at an industrial site is contaminated with γ -hexachlorocyclohexane (HCH) and α-HCH (i.e., lindane) (0.3-0.5 ppm). Other contaminants in the 1-15 ppm range include 1,2,4-trichlorobenezene (TCB), 1,2-dichlorobenzene (DCB), 1,3-DCB, 1,4-DCB, chlorobenzene (CB), benzene, trichloroethene (TCE) and cis-1,2-dichloroethene (cDCE). The aquifer consists of a shallow layer of soil over fractured dolomite, where most of the contaminant mass resides. The objective of this study was to compare 1) anaerobic reductive dechlorination of the polychlorinated contaminants, followed by aerobic biodegradation of the daughter products (mainly DCBs, CB, and benzene); and 2) aerobic biodegradation of α- and γ-HCH, TCB, DCBs, CB and …